topic Re: "su -" hangs when called inside a shell script. in Operating System - HP-UX

"su -" hangs when called inside a shell script.

Chris Magargee_2 — Wed, 31 Aug 2005 09:24:55 GMT

We have a master shell script thats calls another shell script that does a:

su - -c "<script> $ARGS"

Periodically when the master script calls the sub script, the "su" will hang. You can see the "su" in a ps, but it is not running.

We can kill the "su", rerun the master script and the "su" from the sub script runs fine.

Any thoughts or suggestions would be greatly appreciated.

Thanks!
Chris

Re: "su -" hangs when called inside a shell script.

RAC_1 — Wed, 31 Aug 2005 09:28:33 GMT

Let us isolate the problem first.
su -
Does it work?? If not resolve it and if everything is ok, move on. Run the script.
"<script> $ARGS" Is that OK??
If not check your script.

Put set -vx in script and check what step it failes at. Make sure you run commands with full path names, all required variables are defined.

Re: "su -" hangs when called inside a shell script.

Pedro Cirne — Wed, 31 Aug 2005 09:29:10 GMT

Hi,

Who's running the script? Root?

If it's not root, su will wait for a password.

Enjoy :)

Pedro

Re: "su -" hangs when called inside a shell script.

Pat Lieberg — Wed, 31 Aug 2005 09:29:42 GMT

It looks like you're passing a command along with the su. Is it that command that is hanging? Or, does that command never run?

Re: "su -" hangs when called inside a shell script.

James R. Ferguson — Wed, 31 Aug 2005 09:31:53 GMT

Hi Chris:

Unless the script issuing the 'su' is running as 'root', 'su' will prompt for a password for the account to which you are attmpting to switch. The problem is that you cannot supply the password except in an interactive way; i.e. redirection from file will not work.

Regards!

...JRF...

Re: "su -" hangs when called inside a shell script.

Chris Magargee_2 — Wed, 31 Aug 2005 10:04:50 GMT

To answer some of the questions.

1) It is being run by root.
2) The su command runs by hand works fine.
3) The su itself appears to hang, we never receive the login banner from the "su -".

Thanks!
Chris

Re: "su -" hangs when called inside a shell script.

Pedro Cirne — Wed, 31 Aug 2005 10:53:57 GMT

Hi,

I think that some environment variable is missing.

Are you running this script from cron?

If you run it from cron you don't have the environement variables defined of the user root and they are not passed to the user when you su to it.

Check:

#man su
#man cron

Enjoy :)

Pedro

Re: "su -" hangs when called inside a shell script.

Chris Magargee_2 — Wed, 31 Aug 2005 14:28:52 GMT

Running it from the command line.....

Re: "su -" hangs when called inside a shell script.

Tim Nelson — Wed, 31 Aug 2005 14:44:26 GMT

What login banner ? su - may read the new users profile but that is about it other than your command you are telling it to run.

Re: "su -" hangs when called inside a shell script.

Mel Burslan — Wed, 31 Aug 2005 15:33:04 GMT

in your scrip, just before the line, running the su command, insert a line

set -x

and right after su line, insert another one containing, guess what:

set +x

and run your script. You may see why and where it stops. If you see the su command getting executed, then try starting your script called from the su command with "set -x" and ending it with "set +x", it will show you the variable assignments made on the fly or what it is waiting for etc.

hope this helps